The Epidemiology and Genetics (E&G) Core, under the direction of Dr. Frank Hu, provides members with access to data and biological specimen banks from large prospective cohort studies including the Nurses' Health Studies (based at Brigham Women's Hospital), the Health Professionals Health Study (based at the Harvard School of Public Health), the Framingham Heart Study (based at Boston University), Project Viva (based at Harvard Medical School), Boston Puerto Rican Health Study (based at Northeastern University and Tufts University). The Core also provides consultation services in design and analysis for epidemiologic studies with a focus on obesity and nutrition (as exposure or outcome) and for epidemiologic studies aimed at understanding the biologic basis of obesity and related phenotypes through the use of genetics and ?omics technologies. The resources offered by the core have been central to the contributions of large GWAS studies including the GIANT consortium (based at Broad Institute and Children's Hospital) and CHARGE consortium (based at MGH), and fosters bidirectional cross-talk between basic and population scientists in the analysis of candidate genes for obesity and altered nutrient metabolism and on the translation of findings in animal models to human populations. In the last 4-year cycle (2012-2016) services provided by the core resulted in the publication of 170 manuscripts ?an increase from 124 in the previous 5-year competitive renewal cycle (2007- 2012)? including 13 manuscripts published in high impact medical journals (NEJM, JAMA, Lancet, BMJ). In this competitive renewal we propose to further expand data access to include cohorts where hypotheses regarding intergenerational effects of parental exposures on offspring obesity and related phenotypes can be tested, as well as expanded access to and analytical support for projects involving metabolomics and gut microbiome data from the prospective cohorts available through the core.